1. Field of the Invention
This invention relates in general to battery charger arrangements for portable battery operated devices, and more particularly to a battery charger arrangement suitable for use with portable radio communication devices in vehicular and/or other mobile environments.
2. Description of the Prior Art
Portable battery operated devices have benefited from remarkable improvements in battery life and battery charging facilities. Preferably, a portable battery operated device can be recharged in its normal use environment. Although certain portable battery operated devices are normally used near electrical outlets providing unlimited power supply, in many applications, the portable battery operated device is used for extended periods of time in an open outdoor and/or mobile application environment, where there is no readily available unlimited power source such as a wall outlet. In these mobile applications, there may only be available a vehicular battery power supply or other such mobile battery power supply as the only source for recharging a portable device's rechargeable battery. For example, a portable radio, such as utilized by government, police, and fire rescue service personnel may only have available the battery power source of their vehicles to provide recharge to their battery operated portable radios. Additionally, cellular phones and other such portable communication devices are typically operated from a battery source and when used in mobile or outdoor applications, may only have available a battery power source from a local vehicle, such as a car or boat or other such mobile environment providing a battery power source for recharging the cellular radio or other communication device.
When such a portable battery operated device requires recharging of the rechargeable battery, typically, a battery charging arrangement, such as via an adapter to the battery power source of the vehicle, is provided for charging the rechargeable battery of the portable device. Unfortunately, such arrangements in the past have provided a constant drain on the battery power supply of the vehicle, even when the portable battery operated device is not being recharged. This continuous drain on the vehicular battery power source tends to put a strain on the battery of the vehicle, which if left unattended for a significantly long time can deplete the battery of the vehicle or substantially weaken it to the point of reducing its capability to provide a starting charge for the vehicle's engine. This can be particularly dangerous in frigid climates where the power source of the vehicle must reliably start the vehicle to allow operation of the vehicle to commute to safety under harsh weather conditions. Additionally, where police and safety concerns are at issue, a reliable vehicle power source is a must.
Therefore, there is a need to eliminate those specific disadvantages of the prior art as discussed above, and particularly to maintain maximum power available from a mobile and/or vehicular battery power source while providing ready charging facilities for a portable battery operated device, such as a portable communication radio.